Diabetic retinopathy is one of the most feared complications of type 2 diabetes mellitus. It damages the delicate microvessels of the retina, and macular thickening and macular edema are among the leading causes of blindness in affected patients. The condition is particularly insidious because early stages often produce no obvious symptoms, which contributes to frequent underdiagnosis. Data from a national screening program in Singapore cited by the researchers indicate that initial retinopathy signs tend to appear roughly eight years after diabetes onset, with progression across disease stages occurring within just one to two years. That narrow window makes reliable early screening markers a pressing clinical need.

The research team, led by Lei Wang and colleagues at the Department of Endocrinology and Metabolism of The First People’s Hospital of Hefei, in collaboration with Bengbu Medical University, focused on an understudied angle: the role of serum uric acid. Uric acid is the end product of purine metabolism, with roughly three-quarters of circulating levels derived from hepatic metabolism of endogenous purines and one-quarter from dietary intake. About two-thirds is eliminated through the kidneys, which means raw uric acid concentrations are strongly correlated with renal function—a confounder the authors argue has been overlooked in most prior investigations of uric acid and retinopathy.

To correct for this, the team normalized uric acid against serum creatinine, producing the serum uric acid-to-creatinine ratio, or SUA/SCr. Because creatinine reflects kidney clearance capacity, dividing by it compensates for renal dysfunction and better reflects the net endogenous urate burden and the associated oxidative stress status. The approach matters clinically: elevated uric acid can promote monosodium urate crystal formation, and accumulating evidence indicates these crystals activate the NLRP3 inflammasome, releasing interleukin-1β and interleukin-18 while driving broader inflammatory responses involving TNF-α, interleukin-6, and C-reactive protein. Inflammation is a central driver of retinal microvascular injury, so a marker capturing net urate production could plausibly track disease activity.

Methodologically, the study began with 1,091 patients with type 2 diabetes who visited the hospital’s Department of Internal Medicine between 2022 and 2024. After applying predefined inclusion and exclusion criteria, 427 eligible subjects remained, stratified into 183 with diabetic retinopathy and 244 without. Type 2 diabetes was verified using Chinese guideline criteria, fasting and postprandial glucose, HbA1c, and autoantibody testing to rule out autoimmune diabetes. Retinopathy was diagnosed and graded by dilated fundus examination and fundus photography according to the Early Treatment Diabetic Retinopathy Study Severity Scale, with two masked ophthalmologists independently reviewing images and discrepancies resolved by consensus. Patients with severe renal dysfunction, other ocular diseases, malignancies, active infection, or use of drugs affecting uric acid—such as allopurinol, febuxostat, glucocorticoids, and immunosuppressants—were excluded.

The statistical architecture was layered. Spearman rank-order correlation analysis evaluated associations between retinopathy status and clinical variables; univariable binary logistic regression screened potential risk factors; and variables reaching P<0.05 entered a multivariable logistic regression model. A post-hoc power calculation confirmed that with an assumed odds ratio of 1.22, an alpha of 0.05, and a case-to-noncase ratio of 1:1.3, the sample of 427 provided adequate statistical power. Receiver operating characteristic (ROC) analysis then quantified discrimination, and C-statistics were compared via DeLong’s test, supplemented by net reclassification improvement (NRI) and integrated discrimination improvement (IDI) metrics to measure incremental predictive value.

The results painted a consistent picture. Baseline comparisons showed significant between-group differences in age, disease duration, HbA1c, albumin, liver enzymes, total bilirubin, triglycerides, serum uric acid, and SUA/SCr, while sex, C-peptide, fasting plasma glucose, cholesterol fractions, glomerular filtration rate, and creatinine showed no differences. Spearman analysis revealed that retinopathy status correlated positively with age, disease duration, HbA1c, uric acid, and SUA/SCr, and negatively with C-peptide, albumin, and bilirubin. In the multivariable model, elevated SUA/SCr remained independently associated with retinopathy, with an odds ratio of 1.220 (95% CI: 1.015–1.465)—a 1.22-fold higher odds per unit increase after adjustment for total bilirubin, triglycerides, total cholesterol, and LDL-C.

The predictive performance numbers are where the story becomes nuanced. SUA/SCr alone discriminated retinopathy with an AUC of 0.774 (95% CI: 0.720–0.827), a moderate value. The optimal cut-off was 3.68, corresponding to a sensitivity of 79.8% and specificity of 67.2%—meaning the ratio catches most cases but flags a meaningful share of false positives. When SUA/SCr was added to a baseline model containing sex, age, diabetes duration, and HbA1c, the C-statistic rose from 0.655 to 0.676. The IDI reached statistical significance at 0.021 (P=0.006), but the NRI of 0.140 did not (P=0.187). Interestingly, adding raw uric acid to the same baseline model produced a significant NRI of 0.253 (P=0.017) and an IDI of 0.017 (P=0.008), suggesting the creatinine-corrected ratio provides limited supplementary information beyond uric acid itself in this cohort.

The authors interpret these findings cautiously. SUA exhibits dual redox properties and may exert context-dependent antioxidant or pro-oxidant effects, so elevated uric acid does not directly trigger oxidative stress. Clinical evidence remains inconsistent: one Turkish study found no significant differences in ischemia-modified albumin or total oxidant and antioxidant capacity between uncomplicated type 2 diabetes patients with elevated versus normal uric acid. Yet in patients with retinopathy, elevated uric acid may shift toward pro-oxidant activity, promoting retinal inflammatory injury. Mechanistically, hyperglycemia triggers oxidative stress, accumulation of advanced glycation end products, and upregulation of vascular endothelial growth factor—core drivers of retinopathy—while elevated uric acid suppresses endothelial nitric oxide synthesis, activates the renin-angiotensin system, and under hyperglycemic conditions may exacerbate retinal inflammation and activate the Notch signaling pathway.

The study’s limitations are explicitly acknowledged. As a single-center cross-sectional investigation, it can demonstrate association but not causality, and reverse causality is possible: renal and vascular alterations accompanying retinopathy could affect renal urate excretion and handling, in turn influencing the SUA/SCr ratio. Limited sample size, single-region enrollment, and uncollected information on hypoglycemic agents, diet, and physical activity may introduce selection bias and residual confounding. The NRI and IDI analyses are also sensitive to sample size, which may limit the reliability of the incremental performance estimates. Still, the authors conclude that SUA/SCr was significantly associated with diabetic retinopathy and may serve as a supportive auxiliary indicator for identifying high-risk patients with type 2 diabetes—potentially helping clinicians target interventions for diabetic microvascular complications when integrated with comprehensive ophthalmic evaluations including visual acuity testing, dilated fundus examination, fundus photography, and OCT assessment. Further large-scale, prospective, externally validated studies will be needed to confirm its clinical utility.

Subject of Research: Health & Medicine

Article Title: Correlation between serum uric acid-to-creatinine ratio and diabetic retinopathy in type 2 diabetes mellitus patients

Article References: Wang, L., Zhu, Z., Gong, Y., & Wang, G. (2026). Correlation between serum uric acid-to-creatinine ratio and diabetic retinopathy in type 2 diabetes mellitus patients. Frontiers in Endocrinology, 17, Article 1977560. https://doi.org/10.3389/fendo.2026.1977560

Image Credits: AI Generated

DOI: 10.3389/fendo.2026.1977560

Keywords: diabetic retinopathy, type 2 diabetes, serum uric acid, biomarkers, ophthalmology, endocrinology, Correlation, between, serum, uric, acid-to-creatinine, ratio

The renaming of polycystic ovary syndrome to polyendocrine metabolic ovarian syndrome reflects a growing recognition among endocrinologists that the condition extends far beyond the ovaries. What was once framed primarily as a gynecological problem characterized by irregular ovulation and cystic-appearing ovaries is now understood as a systemic endocrine disorder involving insulin resistance, altered androgen production, and disordered energy metabolism. This reframing matters for the dementia question because it places PMOS squarely within a family of metabolic conditions already known to influence brain aging. Type 2 diabetes, obesity, and metabolic syndrome have each been associated in large population studies with increased dementia risk, and the mechanisms implicated in those associations overlap substantially with the pathways the review’s authors highlight.

Insulin resistance deserves particular attention when considering how PMOS might connect to Alzheimer’s disease. The brain is an insulin-responsive organ, and insulin signaling in the central nervous system participates in neuronal survival, synaptic plasticity, and the clearance of amyloid-beta, the protein fragment that accumulates in the plaques characteristic of Alzheimer’s pathology. Some researchers have even described Alzheimer’s disease as carrying features of an insulin-resistant state of the brain, sometimes informally labeled type 3 diabetes, although that phrase remains contested and should not be read as a claim that Alzheimer’s is simply diabetes of the brain. What is better established is that peripheral insulin resistance, of the kind frequently observed in PMOS, correlates with reduced cerebral glucose metabolism and altered amyloid handling in imaging studies of middle-aged and older adults.

Obesity adds a second plausible conduit between PMOS and dementia. Adipose tissue is not merely a passive energy depot; it is an active endocrine organ that secretes inflammatory cytokines, adipokines, and other signaling molecules. Chronic low-grade inflammation driven by excess visceral fat has been linked to vascular damage, blood-brain barrier dysfunction, and accelerated cognitive decline in multiple cohorts. Midlife obesity in particular has emerged as a consistent risk factor for later-life dementia in observational research, while the relationship with obesity in late life is more complicated and sometimes reversed, a pattern that may reflect weight loss preceding clinical dementia. Because women with PMOS commonly carry excess weight from early adulthood, their cumulative lifetime exposure to obesity-related inflammatory and vascular stress may be substantially longer than average.

The vascular dimension is worth emphasizing. PMOS is associated with elevated blood pressure, adverse lipid profiles, and impaired endothelial function, all of which contribute to cerebrovascular disease. Vascular contributions to cognitive impairment and dementia are increasingly recognized as major and potentially modifiable factors, and they frequently coexist with Alzheimer-type pathology. A woman whose PMOS accelerates hypertension or dyslipidemia in her thirties and forties could plausibly enter her sixties and seventies with a brain already bearing the cumulative marks of compromised blood flow, small vessel damage, and microbleeds. This pathway would not require PMOS to act independently on neural tissue at all; it would simply extend the syndrome’s known cardiometabolic consequences into the cerebral circulation.

Androgens represent a third candidate mechanism, and one that is less well understood. PMOS is characterized by elevated ovarian or adrenal androgen production, and androgen signaling interacts with estrogen pathways in ways that vary across the life course. Estrogen has long been studied for its neuroprotective properties, and the sharp decline of estrogen at menopause has been proposed as one reason women face higher Alzheimer’s risk than men overall. How chronically elevated androgens, altered estrogen-to-androgen ratios, and the hormonal shifts of midlife combine in women with PMOS remains largely uncharted. Some animal studies suggest androgen excess can influence hippocampal structure and function, but translating those findings to human cognitive aging requires far more evidence.

The cognitive findings described in the review, mild but reproducible impairments in executive function and memory among PMOS patients, align with patterns seen in other metabolic and psychiatric conditions. Executive function, which governs planning, working memory, and cognitive flexibility, is particularly sensitive to vascular health and to depression, both of which are more common in PMOS. It is therefore possible that some of the cognitive differences observed in younger and middle-aged PMOS populations reflect mood symptoms, sleep disturbance, or metabolic burden rather than incipient neurodegenerative disease. Depression and anxiety, which the review notes are common in PMOS, are themselves established risk factors for later dementia, adding yet another thread to an already tangled web of associations.

Disentangling these threads is the central methodological challenge facing this field. Most available evidence comes from cross-sectional studies or administrative databases, which can identify associations but cannot establish that PMOS causes dementia or that treating PMOS would lower dementia risk. Confounding is a serious concern: women diagnosed with PMOS differ from unaffected women in weight, socioeconomic factors, healthcare utilization, and comorbid conditions, any of which could account for apparent differences in cognitive outcomes. Reverse causation is unlikely in this direction, since PMOS begins in reproductive years long before dementia onset, but selection bias in who gets diagnosed and who gets studied remains a real limitation. The review’s authors acknowledge these gaps explicitly, which is appropriate given the state of the evidence.

Large longitudinal cohorts that follow women with well-characterized PMOS from midlife into older age would be the most direct way to test whether the syndrome independently predicts dementia incidence. Such studies would need to measure metabolic markers serially, distinguish between the different phenotypic presentations of PMOS, and account for treatments that may themselves modify risk. Metformin, the most commonly prescribed medication for insulin resistance in PMOS, has been examined in some dementia-prevention research with mixed results, and oral contraceptives, another mainstay of PMOS management, alter hormonal milieu in ways whose long-term neurological consequences are incompletely mapped. Lifestyle interventions that improve insulin sensitivity and reduce weight are already recommended for PMOS and carry well-documented benefits for vascular and metabolic health, so any overlap with dementia-prevention strategies would be clinically convenient.

The demographic stakes are considerable. Women constitute roughly two-thirds of people living with Alzheimer’s disease, a disparity only partly explained by longer female life expectancy. If a common condition affecting ten to fifteen percent of women modulates that risk, even modestly, the population-level impact could be substantial. At the same time, there is a risk of overinterpreting preliminary associations in ways that alarm patients. The current evidence does not establish that most women with PMOS will develop dementia, nor does it identify a specific age at which risk diverges. What it does establish is a credible biological rationale and enough suggestive clinical signal to justify rigorous investigation.

For clinicians caring for women with PMOS today, the practical message is continuity rather than novelty. The same measures already recommended to reduce the syndrome’s cardiometabolic burden, including weight management, physical activity, glycemic control, and attention to blood pressure and lipids, are the measures most consistently associated with preserved cognitive health in aging populations. Framing PMOS as a lifelong condition with consequences extending into the brain’s later years may help motivate sustained engagement with those interventions during the decades when they matter most. It also underscores the importance of integrating reproductive, metabolic, and neurological perspectives rather than treating each specialty’s concerns in isolation, a lesson that extends well beyond this single syndrome to the broader study of how women’s health across the life course shapes the aging brain.

Subject of Research: Potential association between polyendocrine metabolic ovarian syndrome and Alzheimer's disease and dementia

Article Title: PMOS/PCOS may be linked to Alzheimer's disease and dementia

Article References: PMOS/PCOS may be linked to Alzheimer's disease and dementia. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: PMOS, PCOS, Alzheimer's disease, dementia, insulin resistance, obesity, women's health, endocrinology, metabolic syndrome, brain health, executive function, Journal of the Endocrine Society

The research team, led by Anastasia Trouva of Karolinska Institutet together with colleagues in Sweden and Norway, did not set out to run a new trial. Instead, they mined data from two earlier randomized, double-blind, placebo-controlled studies, the Pilot study and PregMet, in which pregnant women with PMOS had been assigned to metformin or placebo from the first trimester until delivery. Blood samples had been drawn at inclusion, between gestational weeks 5 and 12, and again at weeks 19, 32 and 36. That unusually dense sampling schedule allowed the investigators to reconstruct how thyroid function evolved over time and to test whether that evolution predicted subsequent metabolic markers, rather than simply correlating two snapshots taken at the same moment.

The metabolic readouts in the analysis were the standard currency of insulin resistance research. Fasting and post-load glucose were measured during 75-gram oral glucose tolerance tests at baseline, week 19 and week 32, with an additional fasting glucose at week 36. Fasting insulin was quantified centrally by ELISA, and the two values were combined into the homeostatic model assessment of insulin resistance, HOMA-IR, a proxy index calculated as fasting glucose multiplied by fasting insulin and divided by 22.5. Thyroid function was characterized through serum TSH and free thyroxine, with thyroid peroxidase antibodies assessed to flag autoimmune thyroid disease. None of the participants had overt hypothyroidism, and TSH values stayed within the manufacturer’s reference range throughout.

At entry into the trials, the women carried a mean body mass index of 28.9, at the upper edge of the overweight range, and a mean HOMA-IR of 3.2, a value generally interpreted as insulin resistance in non-pregnant populations. That baseline metabolic burden is not incidental. Insulin resistance is a pathophysiological cornerstone of PMOS, present in most affected women independently of body weight, and it compounds the natural insulin resistance of pregnancy, which intensifies sharply after mid-gestation as placental hormones rise. Women with PMOS face roughly a threefold increased risk of gestational diabetes compared with their peers, making any signal that tracks metabolic decline in this group clinically interesting.

The central result of the new analysis is an inverse one: the smaller the rise in TSH across pregnancy, the higher the glucose levels that followed. A one milliunit-per-liter smaller increase in TSH between baseline and week 19 corresponded to post-load glucose at week 19 that was 0.24 millimoles per liter higher. The same pattern held later in pregnancy, with smaller TSH increases from baseline to week 32 and to week 36 predicting higher fasting glucose at week 36. Free thyroxine told a parallel story. Lower fT4 at baseline predicted higher fasting insulin at weeks 19 and 36, and lower fT4 at weeks 19 and 32 predicted higher insulin and HOMA-IR at week 36. A smaller TSH rise was also linked to higher HOMA-IR at week 32.

Crucially, these associations emerged independently of whether the women were taking metformin or placebo. The statistical models included treatment group as a covariate, and interaction tests found no evidence that the drug modified the thyroid-metabolism links. Metformin did leave its own fingerprint: the treated group showed significant early-pregnancy reductions in insulin and HOMA-IR that the placebo group did not. But by the later trimesters the two arms converged, echoing the consistent finding from prior trials that metformin, despite its insulin-sensitizing credentials, has not reduced the incidence or severity of gestational diabetes in women with PMOS. The thyroid signal, in other words, persisted beneath and beyond the pharmacological noise.

Why would a blunted TSH rise or lower thyroxine foreshadow worsening insulin resistance? The physiology is plausible even if causality remains unproven. Thyroid hormones are master regulators of metabolic rate, stimulating hepatic glycogenolysis and gluconeogenesis, promoting adipose lipolysis, and modulating pancreatic secretion of insulin and glucagon. They also influence hepatic glucose production through a sympathetic neural pathway running from the hypothalamic paraventricular nucleus to the liver. In a healthy pregnancy, TSH drifts slightly upward from the first trimester toward term while free thyroid hormones dip minimally. A failure to mount that normal TSH increase, or a relatively low free thyroxine level, could reflect a thyroid axis that is not keeping pace with the metabolic demands of gestation, leaving glucose regulation to strain against a rising tide of placental insulin resistance.

The authors are careful to frame the work as exploratory and hypothesis-generating rather than practice-changing. Because the analyses are observational in nature, with no randomization to thyroid function, residual confounding cannot be excluded, and body mass index absorbed a substantial share of the associations in adjusted models, a reminder that adiposity shapes both thyroid physiology and insulin action. The researchers also note methodological caveats: glucose was measured locally at participating hospitals while insulin and thyroid markers were assayed centrally, trimester-specific reference ranges for thyroid hormones were unavailable, and immunoassay-based free thyroxine measurements can be influenced by the pregnancy-induced changes in thyroid-binding proteins. Whether thyroid parameters add predictive power beyond established risk factors such as BMI and baseline HOMA-IR remains an open question for future studies.

Even with those caveats, the study adds a distinctive piece to a growing puzzle. Previous work in non-PMOS populations has linked declining or low-normal free thyroxine to less favorable metabolic profiles and to gestational diabetes, and hypothyroxinemia in the second trimester has been associated with the condition. What is new here is the longitudinal, within-pregnancy dimension in a high-risk group, and the observation that the change in TSH, not merely its absolute value, carries information. A prior study in non-pregnant women with PMOS found that TSH at or above 2 milliunits per liter was associated with insulin resistance, yet the women in the current cohort mostly sat below that threshold, suggesting that even subtle shifts within the normal range may matter when metabolic vulnerability is already high.

The practical implications are likely to unfold slowly. If confirmed in prospective cohorts designed to test mechanism and prediction, thyroid trajectories could eventually complement existing metabolic markers in identifying pregnant women with PMOS who are drifting toward glucose intolerance, opening a window for earlier intervention in a condition where prevention has proven stubbornly difficult. For now, the message is one of biological insight rather than clinical prescription: in pregnancy, the thyroid and the pancreas appear to be in constant conversation, and in women with PMOS, a quieter thyroid conversation may foreshadow a louder metabolic one.

Subject of Research: Associations between maternal thyroid function and insulin resistance during pregnancy in women with polyendocrine metabolic ovarian syndrome

Article Title: Maternal thyroid function and subsequent markers of insulin resistance in pregnant women with polyendocrine metabolic ovarian syndrome

Article References: Trouva, A., Vanky, E., Alvarsson, M., Calissendorff, J., Åsvold, B. O., Ujvari, D., & Hirschberg, A. L. (2026). Maternal thyroid function and subsequent markers of insulin resistance in pregnant women with polyendocrine metabolic ovarian syndrome. Frontiers in Endocrinology, 17, Article 1884684. https://doi.org/10.3389/fendo.2026.1884684

Image Credits: AI Generated

DOI: 10.3389/fendo.2026.1884684

Keywords: thyroid function, insulin resistance, pregnancy, PCOS, PMOS, gestational diabetes, TSH, free thyroxine, HOMA-IR, metformin, endocrinology, glucose metabolism

The study, led by Madhulika L. Mahashabde and Sai Karthik Guniganti of the Department of General Medicine at Dr. D.Y. Patil Vidyapeeth in Pune, enrolled 110 adults with type 2 diabetes and compared four candidate markers head to head. The prespecified composite outcome captured the presence of at least one of the three major microvascular complications of diabetes: diabetic retinopathy, diabetic kidney disease and diabetic peripheral neuropathy. Among the participants, 64, or 58.2 percent, had at least one such complication. The researchers then asked a deceptively simple question with profound clinical implications: which of these four blood-based numbers best separates patients with microvascular damage from those without it?

The answer, measured by the area under the receiver operating characteristic curve, or AUC, was remarkable. The triglyceride-glucose index, known as TyG, achieved an AUC of 0.993 with a 95 percent confidence interval stretching from 0.984 to 1.000, a figure so close to perfect discrimination that the authors themselves flag it as unusually high. Glycated haemoglobin, the gold-standard marker of long-term blood sugar control, reached 0.971. The triglyceride-to-HDL-cholesterol ratio followed at 0.959. The homeostatic model assessment of insulin resistance, HOMA-IR, which requires a fasting insulin measurement and has long been considered the reference standard for quantifying insulin resistance in research settings, trailed at 0.810.

Statistical rigour underpinned these comparisons. The team used DeLong confidence intervals for each AUC and then applied DeLong’s test for all six pairwise comparisons, adjusting the resulting p-values with the Holm-Bonferroni method to control the family-wise error rate. After this adjustment, TyG, TG/HDL-C and HbA1c each outperformed HOMA-IR with adjusted p-values below 0.001, while no statistically significant differences separated the three leading markers from one another. In other words, the two insulin-free surrogates, calculated from fasting biochemistry that costs a fraction of an insulin assay, performed at least as well as the established glycemic marker and clearly better than the insulin-based index they were designed to replace.

The biological logic behind these indices is worth unpacking. Insulin resistance drives a characteristic lipid pattern: the liver pumps out more very-low-density lipoprotein particles, triglycerides rise, and high-density lipoprotein cholesterol falls. The TyG index captures this by combining fasting triglycerides with fasting plasma glucose in a logarithmic formula, reflecting the fact that insulin-resistant tissue allows both circulating fats and sugars to accumulate. The TG/HDL-C ratio distils the same physiology into a single fraction. Because insulin resistance is increasingly recognised as a contributor to microvascular complications, including retinopathy, nephropathy and neuropathy, these surrogates may be flagging the underlying metabolic milieu that damages small vessels, rather than merely the degree of glycemic excursion that HbA1c measures.

Exploratory cut-offs emerged from the analysis using the Youden index, which maximises the sum of sensitivity and specificity. For TyG, the cut-off was 9.23 or above, at which the index showed 93.8 percent sensitivity and 100 percent specificity for identifying prevalent microvascular complications. For TG/HDL-C, the exploratory threshold was 3.40 or above. These figures, if they hold up under external validation, would mean a single fasting blood panel could triage patients for complication screening without waiting for an insulin assay or even a glycated haemoglobin result.

Beyond discrimination, the researchers examined whether these markers add genuine incremental value to existing models. Multivariable associations were assessed using Firth’s penalised-likelihood regression, a technique designed for small samples where conventional maximum-likelihood logistic regression can produce unstable or infinitely large coefficient estimates. Each one-standard-deviation rise in TyG and TG/HDL-C remained significantly associated with the composite outcome after Firth penalisation, with p-values of 0.002 and 0.003 respectively. Calibration was assessed using the intercept, slope and Brier score, and decision curve analysis explored the net benefit of using each marker at various threshold probabilities. Adding TyG to a base model containing HbA1c and HOMA-IR yielded an integrated discrimination improvement, or IDI, of 0.219, indicating that TyG carries information about microvascular complications that the established markers do not fully capture.

The authors are careful, and rightly so, about the limits of what this study can claim. The unusually high AUCs, particularly TyG’s 0.993, may reflect the disease spectrum of a tertiary-care referral population, where patients tend to have more advanced disease and more pronounced metabolic derangement than the general diabetic population. The researchers explicitly state that these figures should be regarded as upper bounds rather than realistic expectations of performance in community settings. The cross-sectional design means the study identifies prevalent complications at a single point in time; it makes no claim of predictive or screening performance, and the exploratory cut-offs require prospective, multicentre external validation before any triage use.

India carries a disproportionate share of the global diabetes burden, and microvascular complications, including blindness, kidney failure requiring dialysis and disabling neuropathy, impose enormous human and economic costs. If the Pune findings replicate in larger, multicentre, prospective cohorts, the implications for resource-constrained health systems could be transformative. A fasting blood panel already drawn for routine lipid and glucose monitoring could double as a complication triage tool, flagging patients who need retinal imaging, urinary albumin-to-creatinine ratio testing or nerve conduction studies, without adding a single new test to the workflow.

For now, the study stands as a provocative proof of concept from Western India: two numbers calculated from tests already sitting in every clinic’s biochemistry report, the triglyceride-glucose index and the triglyceride-to-HDL-cholesterol ratio, matched glycated haemoglobin and beat the insulin-based HOMA-IR in identifying the microvascular fingerprints of type 2 diabetes. The road from exploratory cut-offs to validated triage tools runs through prospective validation, but the destination, a cheaper, faster and more accessible way to spot diabetes’ most feared complications, is one worth watching closely.

Subject of Research: Triglyceride–glucose index and triglyceride/HDL-cholesterol ratio versus HbA1c and HOMA-IR for identifying microvascular complications in type 2 diabetes: a cross-sectional comparative diagnostic accuracy study from Western India

Article Title: Triglyceride–glucose index and triglyceride/HDL-cholesterol ratio versus HbA1c and HOMA-IR for identifying microvascular complications in type 2 diabetes: a cross-sectional comparative diagnostic accuracy study from Western India

Article References: Mahashabde, M. L., & Guniganti, S. K. (2026). Triglyceride–glucose index and triglyceride/HDL-cholesterol ratio versus HbA1c and HOMA-IR for identifying microvascular complications in type 2 diabetes: a cross-sectional comparative diagnostic accuracy study from Western India. BMC Endocrine Disorders. https://doi.org/10.1186/s12902-026-02674-4

Image Credits: AI Generated

DOI: 10.1186/s12902-026-02674-4

Keywords: Type 2 Diabetes, Insulin Resistance, TyG Index, HbA1c, Diagnostic Accuracy, Diabetic Complications, Clinical Research, Endocrinology, Triglyceride, glucose, index, HDL-cholesterol

The study, led by Sophie Monnerat and Sven Lustenberger, who contributed equally, under the supervision of Mirjam Christ-Crain at the University Hospital Basel, was a double-blind, randomised, placebo-controlled crossover trial registered as NCT06277336 and funded by the Swiss National Science Foundation. Fifteen healthy adults, seven of them female, with a mean age of 28 years (standard deviation, 8), attended three study visits each. Because each participant received all three treatments in randomised order, the crossover design allowed each person to serve as their own control, reducing variability and increasing statistical power despite the modest sample size.

To recreate the syndrome of inappropriate antidiuresis in the laboratory, the researchers used a combination of desmopressin, a synthetic vasopressin analogue; water loading; and hypotonic saline. Desmopressin suppresses the kidneys’ ability to excrete free water, mimicking the inappropriate vasopressin activity seen in patients. Water loading then floods the system, and hypotonic saline completes the picture, driving serum sodium down into the hyponatremic range. The result is a controlled, reversible model of the biochemical derangement that affects millions of people worldwide, from those with lung cancer to those taking certain antidepressants.

Once the artificial syndrome was established, participants received one of three treatments as a three-hour intravenous infusion: high-dose [Pyr¹]apelin-13 at 1800 nanomoles, low-dose [Pyr¹]apelin-13 at 180 nanomoles, or placebo. [Pyr¹]apelin-13 is the pyroglutamated form of the 13-amino-acid apelin peptide, the predominant circulating isoform in humans and the version most studied for its vasopressin-antagonising properties. The primary endpoint was cumulative urine output from the start of the infusion until one hour after its completion, a window chosen to capture the drug’s full diuretic effect.

The verdict was unambiguous. Neither the high dose nor the low dose of [Pyr¹]apelin-13 produced a clinically relevant difference in urine output compared with placebo. In rodents, apelin analogues had reliably increased urine output in hyponatremia models, but the corresponding human data had been lacking until now. This trial provides those data, and they do not support the translational promise that the animal work suggested.

Why did the peptide fail in humans when it worked in mice? Several explanations are plausible. Rodent models of hyponatremia may not faithfully reproduce the human vasopressin axis, and the apelin receptor system may differ between species in ways that matter for drug response. The artificially induced syndrome, while biochemically convincing, may not capture the full complexity of the clinical condition, where vasopressin activity is chronic and tissue-level adaptations have had time to develop. It is also possible that the infusion doses, though chosen to span a wide range, did not achieve sufficient receptor occupancy in the relevant renal compartments, or that the peptide’s short half-life limited its diuretic effect within the observation window.

The negative result is particularly notable because the trial was designed with rigorous methodology. The double-blind, placebo-controlled crossover design, the use of a validated artificial model of inappropriate antidiuresis, and the pre-specified primary endpoint all reflect a high standard of clinical pharmacology. The study was conducted across multiple institutions, with collaborators at the University of Edinburgh’s Centre for Cardiovascular Science, the Royal Infirmary of Edinburgh, the University of Cambridge, Erasmus Medical Center in Rotterdam, and LMU University Hospital in Munich, bringing together expertise in endocrinology, renal medicine, and cardiovascular pharmacology.

For patients with the syndrome of inappropriate antidiuresis, the current treatment landscape remains limited. Fluid restriction is the mainstay, but it is often poorly tolerated. Vasopressin receptor antagonists exist but carry risks and are not suitable for everyone. The hope that apelin-based therapies could offer a gentler, physiology-mimicking alternative now faces a significant setback. The peptide’s failure to increase urine output in this controlled setting suggests that the vasopressin-antagonising properties observed in animal models do not translate simply to human renal physiology.

Yet the trial should not be read as the end of the apelin story. The study tested only acute intravenous administration in healthy volunteers with an artificially induced condition. Chronic dosing, different formulations, longer-acting analogues, or patient populations with established disease might behave differently. The artificially induced syndrome, while biochemically convincing, may not capture the full complexity of the clinical condition. Future research may need to explore whether apelin’s role in salt and water homoeostasis operates through mechanisms that require longer exposure or different physiological contexts to become clinically relevant.

The study, published on 16 October 2026 in Nature Communications as an open-access article, received support from the University of Basel, the University Hospital of Basel, and the Swiss National Science Foundation. The authors declared no competing interests. The negative finding, while disappointing for the translational agenda, exemplifies the value of rigorous human trials: they prevent the research community from investing further resources in approaches that do not work, and they redirect attention toward mechanisms that might. In the ongoing effort to understand how the posterior pituitary orchestrates the body’s water balance, apelin has revealed itself to be a more complicated character than the rodent data suggested.

Subject of Research: Health sciences

Article Title: Intravenous [Pyr¹]apelin-13 in Healthy Volunteers with Artificially-Induced Syndrome of Inappropriate Antidiuresis – a double-blind, randomised, placebo-controlled crossover study

Article References: Monnerat, S., Lustenberger, S., Bizzozero, C. A., Chapman, F. A., Santos de Jesus, J., Kustos-Toth, E., Vogt, D. R., Bruce, L., Little, R., Davenport, A. P., Maguire, J. J., Refardt, J., Bidlingmaier, M., Dhaun, N., & Christ-Crain, M. (2026). Intravenous [Pyr¹]apelin-13 in Healthy Volunteers with Artificially-Induced Syndrome of Inappropriate Antidiuresis – a double-blind, randomised, placebo-controlled crossover study. Nature Communications. https://doi.org/10.1038/s41467-026-78333-y

Image Credits: AI Generated

DOI: 10.1038/s41467-026-78333-y

Keywords: apelin, hyponatremia, vasopressin, clinical trial, SIADH, desmopressin, water balance, endocrinology, Intravenous, apelin-13, Healthy, Volunteers

The research team, led by endocrinologists at Basaksehir Cam and Sakura City Hospital affiliated with the University of Health Sciences, analyzed records from 252 patients. The cohort comprised 132 patients with overt Cushing syndrome, subdivided into 75 with Cushing disease, where a pituitary tumor drives excess adrenocorticotropic hormone, and 57 with adrenal Cushing syndrome, where the adrenal gland itself overproduces cortisol. A further 68 patients had mild autonomous cortisol secretion, often abbreviated MACS, a subtle biochemical abnormality frequently detected in adrenal incidentalomas, and 52 patients had nonfunctioning adrenal tumors, or NFAT, which secrete no excess hormone. The investigators compared standard complete blood count parameters across these groups, including total white blood cell count and the individual counts of neutrophils, monocytes, lymphocytes, eosinophils, and basophils, together with two widely used derived indices, the neutrophil-to-lymphocyte ratio and the monocyte-to-lymphocyte ratio.

Cortisol is a potent immunomodulatory hormone, and its chronic excess has long been known to reshape circulating leukocyte populations. Glucocorticoids promote the release of mature neutrophils from the bone marrow, delay their apoptosis, and simultaneously drive the redistribution and death of lymphocytes, producing the classic picture of neutrophilia with relative lymphopenia seen in states of glucocorticoid excess. What has remained uncertain is whether the low-grade, often subclinical cortisol elevation of MACS produces hematological changes that are detectable and comparable to those of overt disease. Resolving this question matters clinically, because MACS is increasingly diagnosed as adrenal imaging becomes more common, yet its systemic consequences remain debated.

The results were clear-cut at the extremes. Total white blood cell count, neutrophil count, monocyte count, and the monocyte-to-lymphocyte ratio were all significantly higher in patients with overt Cushing syndrome than in either the MACS group or the NFAT group, with p values at or below 0.002. The neutrophil-to-lymphocyte ratio, a marker frequently studied in inflammatory and endocrine disease, was significantly elevated in overt Cushing syndrome only in comparison with MACS once the analysis was corrected for multiple comparisons using the Bonferroni method. This pattern indicates that the myeloid expansion characteristic of glucocorticoid excess, with more neutrophils and monocytes relative to lymphocytes, is a feature of overt disease rather than of the milder biochemical state.

In striking contrast, no significant differences emerged between the MACS and NFAT groups on any individual parameter, with all p values exceeding 0.05. The effect sizes separating these two groups were uniformly small, with Cohen’s d values ranging from 0.02 to 0.17, a range conventionally interpreted as negligible. The authors note that any true difference between mild autonomous cortisol secretion and nonfunctioning tumors is likely to be small, although they caution that subtle effects cannot be entirely excluded by a study of this size. In practical terms, a routine blood count cannot currently distinguish a patient with mild cortisol autonomy from one with a hormone-silent adrenal mass.

Beyond group comparisons, the study examined how leukocyte parameters track with biochemical measures of cortisol burden. Neutrophil count, monocyte count, the neutrophil-to-lymphocyte ratio, and the monocyte-to-lymphocyte ratio each correlated positively with multiple cortisol markers, which in this clinical context typically include urinary free cortisol, late-night salivary cortisol, and the dexamethasone suppression test. This dose-response relationship strengthens the biological plausibility of the findings: the more cortisol circulating, the more pronounced the shift toward myeloid cells in the peripheral blood. It also suggests that these inexpensive, routinely measured indices could serve as accessible proxies for the immunological impact of cortisol excess.

To move beyond univariate comparisons, the researchers performed an exploratory linear discriminant analysis, a multivariate statistical technique that seeks linear combinations of variables best separating predefined groups. The analysis aimed to characterize the overall leukocyte profiles of Cushing disease, adrenal Cushing syndrome, MACS, and NFAT. On the primary discriminant axis, basophil count emerged as the parameter with the highest normalized loading. However, the authors themselves flag an important statistical caveat: because basophil counts are small in absolute magnitude, their loadings can be inflated by scale-related artifacts rather than reflecting a genuine biological signal. This transparency is a notable feature of the paper, which consistently frames its multivariate results as exploratory.

Indeed, the authors are explicit that the classification performance of the discriminant model was modest and not validated in an independent cohort. They emphasize that these findings are hypothesis-generating and should not be interpreted as evidence of a validated diagnostic tool or of a pathophysiological continuum linking mild and overt cortisol excess. This restraint matters in a field where machine-learning-style analyses of routine laboratory data are increasingly promoted as diagnostic shortcuts. The study instead delivers a more measured message: overt hypercortisolism leaves a clear myeloid signature in the blood, but mild autonomous cortisol secretion, at least as captured by standard hematological parameters, does not.

The clinical implications cut in two directions. For patients with overt Cushing syndrome, the correlation between myeloid indices and cortisol burden adds to the evidence that chronic glucocorticoid excess produces measurable systemic inflammation-like changes, which may be relevant to the elevated cardiovascular and infectious risk seen in these patients. For the growing population of patients found to have adrenal incidentalomas, the absence of hematological differences between MACS and NFAT suggests that routine blood counts offer no added diagnostic value in characterizing the functional status of such tumors, and that established endocrine testing remains essential.

As a single-center retrospective cross-sectional study, the work has inherent limitations, including the possibility of selection bias and the inability to establish causality or track changes over time within individual patients. Nevertheless, by systematically comparing four clinically distinct adrenal and pituitary states within a single cohort, the study provides one of the clearest pictures to date of where, on the spectrum of cortisol excess, the immune system begins to visibly shift. The answer, apparently, is not at the mild end. Future prospective studies with larger MACS cohorts and longitudinal sampling will be needed to determine whether subtle immune changes emerge over time, and whether any leukocyte signature could eventually complement, rather than replace, the biochemical tests that currently define this enigmatic condition.

Subject of Research: Peripheral leukocyte profiles across clinical forms of hypercortisolism and nonfunctioning adrenal tumors

Article Title: Peripheral leukocyte profiles in different clinical forms of hypercortisolism and nonfunctioning adrenal tumors: a retrospective cross-sectional study

Article References: Burhan, S., Ozkahraman, A. U., Korkmaz Yilmaz, M., Akbulut, S., Cicek, M. Z., Niyazoglu, M., & Hatipoglu, E. (2026). Peripheral leukocyte profiles in different clinical forms of hypercortisolism and nonfunctioning adrenal tumors: a retrospective cross-sectional study. BMC Endocrine Disorders. https://doi.org/10.1186/s12902-026-02668-2

Image Credits: AI Generated

DOI: 10.1186/s12902-026-02668-2

Keywords: Cushing syndrome, mild autonomous cortisol secretion, adrenal incidentaloma, leukocytes, neutrophil-to-lymphocyte ratio, monocyte-to-lymphocyte ratio, cortisol, endocrinology, hematology, linear discriminant analysis, biomarkers, nonfunctioning adrenal tumor

The review, led by Shengyue Jin and colleagues at the Department of TCM Gynecology of Hangzhou TCM Hospital of Zhejiang Chinese Medical University, was designed as a narrative review with a systematic literature search. The team queried PubMed, Web of Science, Embase, and the China National Knowledge Infrastructure from database inception to March 2026, using terms related to PMOS, gut microbiota, microbial metabolites, and microbiota-targeted interventions. Two authors independently screened records, resolved disagreements by consensus, and excluded case reports, letters, conference abstracts, and non-English publications. No meta-analysis was performed. What distinguishes this synthesis from earlier descriptive reviews, the authors contend, is its explicit incorporation of phenotypic heterogeneity, methodological variability, and evidence grading across clinical and preclinical studies, moving the field beyond fragmented associative observations toward a structured, system-level perspective.

The gut microbiota, sometimes described as the host’s second genome, is dominated by the phyla Bacteroidetes and Firmicutes, with contributions from Proteobacteria, Verrucomicrobia, Actinobacteria, and others. It performs essential functions in digestion, energy harvest, vitamin synthesis, immune modulation, and endocrine regulation, and has been recognized as an endocrine-like organ that interacts with sex hormones and insulin. A healthy gut is marked by high bacterial diversity, an intact intestinal barrier maintained by tight junction proteins, and an abundance of beneficial genera such as Bifidobacterium and Lactobacillus. Dysbiosis, by contrast, involves a loss of beneficial microbes, an overgrowth of pro-inflammatory species, and compromised barrier integrity. Accumulating evidence indicates that PMOS is associated with precisely this pattern: decreased microbiota diversity, reduced beneficial bacteria, and increased pro-inflammatory taxa.

Crucially, the relationship runs in both directions. Elevated androgen levels, a hallmark of PMOS driven by enhanced ovarian steroidogenesis, increased adrenal androgen secretion, and insulin resistance, have been linked to reduced gut microbiota diversity, an increased Firmicutes-to-Bacteroidetes ratio, and enrichment of genera including Clostridium, Dorea, and Bilophila. Dihydrotestosterone-induced PMOS rat models show increased body weight, fat deposition, and diminished intestinal flora diversity. Insulin resistance, which affects roughly 50 to 70 percent of PMOS patients, further reshapes microbial ecology: among women with insulin resistance, Bacteroidaceae abundance rises while Prevotellaceae falls, and patients exhibit elevated lipopolysaccharide biosynthesis pathways and heightened inflammatory cytokines. Obesity, present in about half to 60 percent of PMOS cases, amplifies these alterations, with obese patients showing higher concentrations of LBP, GLP-2, succinate, and zonulin family peptides, implying heightened intestinal permeability and compromised barrier function.

The review’s central mechanistic contribution lies in its dissection of microbiota-derived metabolites that link intestinal dysbiosis with metabolic and endocrine dysfunction. Bile acids, regulated through the receptors TGR5 and FXR, emerge as a signaling hub. Animal studies show that ursodeoxycholic acid enhances ovarian morphology and decreases testosterone and insulin levels, while clinical data reveal that elevated Bacteroides, glycodeoxycholic acid, and tauroursodeoxycholic acid correlate with insulin resistance and ovarian dysfunction. Bile acids enhance IL-22 secretion by activating the GATA3 pathway in innate lymphoid cells, and primary bile acid proportions correlate positively with total testosterone and free androgen index, suggesting roles in hyperandrogenism, follicular development, and ovulatory disorders.

Short-chain fatty acids, produced by microbial fermentation of dietary fiber, act as the counterweight. Circulating butyrate is significantly reduced in obese PMOS patients, and butyrate impedes METTL3-mediated FOSL2 m6A methylation, obstructing NLRP3 inflammasome activation and pro-inflammatory cytokine release. SCFAs enhance IL-22 secretion via GPR41 signaling and HDAC inhibition, fortify the intestinal mucosal barrier, and restrain pro-inflammatory responses in dendritic cells and macrophages by activating GPR41/43 and GPR109A receptors, decreasing IL-6 and IL-12 while facilitating Treg differentiation and IL-10 secretion. Given that PMOS patients display Treg/Th17 imbalance, SCFA-mediated restoration of immune homeostasis may represent a viable strategy. SCFAs also stimulate incretin production through FFAR2/3, augmenting glucose-dependent insulin secretion and improving HOMA-IR.

On the damaging side of the ledger, branched-chain amino acids and lipopolysaccharide function as amplifiers of metabolic dysregulation. The BCAA metabolite 3-HIB enhances transendothelial fatty acid transport, stimulating lipid deposition in skeletal muscle and contributing to insulin resistance, while excess BCAAs trigger the mTORC1/S6K1 pathway and disrupt mitochondrial function. Elevated plasma BCAA levels correlate positively with androgen levels, antral follicles, and menstrual irregularity, with PPM1K identified as a causative gene. LPS, a structural component of Gram-negative bacteria, enters the bloodstream through a leaky intestinal barrier, inducing metabolic endotoxemia. It activates the TLR4/NF-κB inflammatory pathway, stimulates TNF-α, IL-1β, IL-6, and IL-8 in granulosa cells, and initiates oxidative stress. Fecal metagenomic data suggest that reduced Bacteroidales may elevate pro-inflammatory LPS levels in follicles, correlating with follicular hypoplasia and elevated AMH.

These mechanistic insights are fueling a wave of microbiota-targeted interventions. Lifestyle modification remains foundational, with ketogenic and Mediterranean diets improving anthropometric, metabolic, and sex hormone profiles, and exercise modalities from high-intensity interval training to yoga enhancing insulin sensitivity and menstrual regularity. Fecal microbiota transplantation from healthy donors partially reduced fat accumulation and modified metabolism-associated bacteria in DHT-induced PMOS mice, while in letrozole-induced rats it enhanced estrous cyclicity, decreased serum androgens, and restored normal ovarian morphology, though no human trials have yet evaluated FMT safety or efficacy in PMOS. Probiotic strains including Lactobacillus plantarum HL2 and Bifidobacterium longum HB3 ameliorated ovarian pathology and diminished testosterone in animal models. Prebiotics show particular promise: inulin supplementation improved glucose tolerance, insulin sensitivity, and ovarian morphology in PMOS models, and a clinical investigation found that 10 grams of inulin daily over three months improved hyperandrogenism, insulin resistance, and dyslipidemia while increasing Bifidobacterium abundance.

Pharmacological agents also intersect with the gut ecosystem. Metformin enhances beneficial bacteria including Akkermansia muciniphila, Clostridium leptum, and Faecalibacterium prausnitzii, reduces plasma LPS and inflammatory mediators, and may normalize altered fecal SCFA levels. GLP-1 receptor agonists such as semaglutide and liraglutide improve weight, hyperandrogenism, and menstrual cyclicity, with semaglutide acting through PI3K/AKT/mTOR and AMPK/SIRT1/NF-κB pathways in animal models. Natural compounds add further depth: resveratrol activates SIRT1/AMPK signaling, inhibits CYP17A1 and HMG-CoA reductase to reduce androgen synthesis, and exerts a prebiotic-like effect on gut microbiota, while berberine restores microbial diversity and structure in PMOS patients. Traditional Chinese medicine formulations including Bailing capsule modulate the LPS-TLR4 inflammatory pathway and enrich SCFA-producing bacteria.

Yet the authors are emphatic about the limits of current evidence. Most included studies are observational or cross-sectional, with a scarcity of large-scale randomized controlled trials and long-term prospective cohort data, leaving causal inference weak. Substantial heterogeneity exists across studies in microbial detection techniques, from 16S rRNA gene sequencing to metagenomic and metabolomic approaches, and in study populations differing in ethnicity, obesity status, and PMOS phenotypic classification. Microbiota-targeted interventions are more likely to exert adjunctive therapeutic effects by improving the metabolic and inflammatory microenvironment rather than serving as independent treatments, and their stability, efficacy reproducibility, and clinical generalizability remain unvalidated. The review calls for well-designed longitudinal studies and randomized controlled trials with strict phenotypic stratification, integrating causal inference approaches and multi-omics analyses. As understanding of the gut–metabolism–endocrine–ovary axis advances, precision intervention strategies based on individual gut microbiota characteristics may offer new therapeutic directions for the long-term management of PMOS and improved overall patient health outcomes.

Subject of Research: Gut microbiota and PMOS: an integrated gut–metabolism–endocrine–ovary axis

Article Title: Gut microbiota and polyendocrine metabolic ovarian syndrome: an integrated gut–metabolism–endocrine–ovary axis

Article References: Jin, S., Zhu, M., Lu, Y., Zhao, J., Zhu, J., & Fang, X. (2026). Gut microbiota and polyendocrine metabolic ovarian syndrome: an integrated gut–metabolism–endocrine–ovary axis. Experimental Biology and Medicine, 251, Article 11058. https://doi.org/10.3389/ebm.2026.11058

Image Credits: AI Generated

DOI: 10.3389/ebm.2026.11058

Keywords: gut microbiota, PMOS, PCOS, insulin resistance, hyperandrogenism, bile acids, short-chain fatty acids, microbiome, endocrinology, ovarian dysfunction, microbiota, polyendocrine

The research team, led by investigators at S.D. Asfendiyarov Kazakh National Medical University in Almaty, analyzed data from a WHO STEPS survey conducted between May and October 2025. Of 3,198 eligible men, 3,083 had testosterone measurements suitable for analysis, and the investigators applied survey weights, stratification, and clustering to ensure their estimates reflected the true structure of the Kazakh male population. The primary outcome was a total testosterone concentration below 8 nmol/L, a cutoff frequently used to flag biochemical hypogonadism, with additional sensitivity analyses at 10 and 12 nmol/L to test whether the associations held at different thresholds. This design-based approach matters because naive analyses of survey data can produce misleading confidence intervals and prevalence estimates.

The headline numbers are straightforward. The observed proportion of men with testosterone below 8 nmol/L was 5.1 percent, or 156 of 3,083 participants, and after weighting the survey-adjusted prevalence came in at 5.3 percent, with a 95 percent confidence interval of 4.4 to 6.2 percent. That figure is lower than some clinic-based estimates from other regions, a reminder that men who walk into endocrinology clinics are not typical of the population at large. But the raw prevalence tells only part of the story. The heart of the paper lies in its regression models, which disentangle the independent contributions of body size, glycemic status, and age to the probability of low testosterone.

In the primary logistic model, which included 2,959 men and adjusted for age, body mass index, and glycated hemoglobin, or HbA1c, the metabolic signals were strong and consistent. Overweight men had roughly double the odds of low testosterone compared with men of normal weight, with an adjusted odds ratio of 2.05. Men with obesity fared far worse still: their odds were more than four and a half times higher, at 4.58, than those of their lean counterparts. Glycemic status showed a parallel gradient. Men whose HbA1c fell in the prediabetes range had 2.39 times the odds of low testosterone, while those in the diabetes range had 3.49 times the odds. In other words, both the degree of adiposity and the severity of dysglycemia tracked closely with the likelihood of biochemical testosterone deficiency.

When testosterone was analyzed as a continuous variable after logarithmic transformation, the same pattern emerged in proportional terms. Overweight was associated with testosterone levels 15.0 percent lower than in normal-weight men, and obesity with levels 24.8 percent lower. Prediabetes-range HbA1c corresponded to levels 19.0 percent lower, and diabetes-range HbA1c to levels 24.5 percent lower. These continuous estimates are informative because they suggest a dose-response relationship rather than a binary cliff: the worse the metabolic profile, the lower the circulating hormone. Importantly, the associations with obesity and dysglycemia remained positive even when the researchers relaxed the diagnostic threshold to 10 or 12 nmol/L, indicating that the findings are not an artifact of one particular cutoff.

Perhaps the most scientifically intriguing result concerns age. Taken on its own, aging appeared to raise the risk: men aged 60 to 69 had 1.84 times the odds of low testosterone compared with men aged 18 to 29. Yet once body mass index and HbA1c were factored in, the direction of the association flipped, yielding an adjusted odds ratio of 0.65, and the effect was no longer statistically significant. The authors interpret this reversal as evidence that the apparent age-related decline in testosterone within this population may be substantially mediated by metabolic factors. Older men in the survey tended to be heavier and more dysglycemic, and it is those characteristics, rather than chronological age itself, that appear to drive much of the association with low testosterone.

This finding resonates with a broader mechanistic literature on the hypothalamic-pituitary-gonadal axis and metabolism. Adipose tissue, particularly visceral fat, is metabolically active: the enzyme aromatase converts testosterone into estradiol, the hypothalamic-pituitary feedback loop responds by suppressing gonadotropin release, and leptin and inflammatory cytokines secreted by fat cells further dampen gonadal steroidogenesis. Hyperglycemia and insulin resistance compound these effects, and the testosterone-glucose relationship is often described as bidirectional, since low testosterone itself can promote insulin resistance and central fat deposition. The Kazakh data cannot establish causation, being cross-sectional, but the strength and consistency of the adiposity and glycemia signals align closely with what these physiological models predict.

The study carries significant public health implications for Kazakhstan and the wider Central Asian region, where population-based endocrine data have historically been scarce. Funded by Kazakhstan’s Ministry of Healthcare under a grant on epigenetics and non-communicable disease prevention, and registered as clinical trial NCT06953180, the survey demonstrates how the standardized WHO STEPS framework can be extended from its traditional focus on cardiovascular risk factors to hormone health. If excess adiposity and dysglycemia are the dominant modifiable correlates of low testosterone, then strategies targeting obesity and prediabetes prevention may carry hormonal benefits alongside their well-established cardiovascular ones. For a country confronting the global epidemic of metabolic disease, the overlap between these two health burdens is a compelling argument for integrated prevention programs.

The authors are careful to draw a crucial clinical boundary: a biochemical reading below 8 nmol/L is not, by itself, a diagnosis of clinical hypogonadism. True hypogonadism requires compatible symptoms, such as reduced libido, fatigue, or loss of muscle mass, together with confirmatory testing, typically including repeated morning measurements and assessment of the hypothalamic-pituitary axis. Cross-sectional biochemical associations describe the population’s hormonal landscape; they do not tell clinicians which individual men need treatment. This caution is especially important in an era when testosterone testing and therapy are increasingly marketed directly to consumers, and it underscores why large, methodologically rigorous population surveys are needed to ground clinical practice in representative evidence.

As an early-access, open-access publication carrying a permanent DOI, the study invites both replication and extension. Future work could follow men over time to test whether weight loss and glycemic control raise testosterone levels, examine free and bioavailable testosterone rather than total concentrations alone, and probe whether behavioral factors measured in STEPS surveys, such as physical activity and alcohol intake, modify the metabolic associations. For now, the message from Kazakhstan is clear and quantifiable: in a nationally representative sample of men, low circulating testosterone clustered tightly around the two great metabolic risk factors of our time, and age, once those factors were accounted for, lost much of its apparent grip. The study reframes male hormone health not as an inevitable consequence of growing older, but as a mirror of metabolic health, one that may be more malleable than conventional wisdom suggests.

Subject of Research: Metabolic correlates of low total testosterone among men in a national Kazakhstan WHO STEPS survey

Article Title: Metabolic correlates of biochemically low total testosterone among men participating in a national WHO STEPS survey in Kazakhstan

Article References: Gizat, D., Shamsutdinova, A., Ibrayeva, A., Ismoldayev, Y., Alchinbayev, M., Shoranov, M., Tanabayeva, S., & Fakhradiyev, I. (2026). Metabolic correlates of biochemically low total testosterone among men participating in a national WHO STEPS survey in Kazakhstan. BMC Endocrine Disorders. https://doi.org/10.1186/s12902-026-02659-3

Image Credits: AI Generated

DOI: 10.1186/s12902-026-02659-3

Keywords: testosterone, hypogonadism, obesity, dysglycemia, HbA1c, Kazakhstan, WHO STEPS survey, endocrinology, metabolic syndrome, cross-sectional study, men's health, public health

The numbers behind this convergence are striking. The DCCT/EDIC study, one of the longest-running investigations of type 1 diabetes, documented an increase in obesity prevalence among patients from just 2 percent at baseline in the 1980s to 28 percent after twelve years of follow-up. The international SWEET registry reported that nearly one in three children and adolescents with type 1 diabetes is now overweight or obese. Meanwhile, observational cohort studies encompassing approximately 1.7 million individuals have found that people with overweight or obesity face a pooled risk ratio of 1.87 for developing type 1 diabetes, a figure that rises to 2.55 when confirmed by islet autoantibody testing. These findings suggest that the relationship between metabolic dysfunction and autoimmune destruction is not coincidental but bidirectional and mechanistically intertwined.

At the heart of this convergence lies a paradox of modern type 1 diabetes treatment. Intensive insulin therapy, while dramatically reducing long-term complications, is itself a major contributor to weight gain and insulin resistance. The review explains that subcutaneous insulin delivery bypasses the liver’s first-pass metabolism, creating peripheral hyperinsulinemia and hepatic hypoinsulinemia. Chronically elevated peripheral insulin levels promote oxidative stress, inflammation, and dysregulation of insulin receptor expression, worsening the very insulin resistance that drives further weight gain. As glycemic control improves, calories that would once have been lost through glucosuria are retained, and alterations in growth hormone and IGF-1 signaling pathways further disrupt normal body composition regulation. The result is a vicious cycle in which higher insulin doses beget more weight gain, which in turn demands even more insulin.

But the influence of obesity on autoimmune diabetes extends far beyond the mechanical effects of insulin therapy. The review details how adipose tissue itself functions as an active immune organ. In obesity, the balance between pro-inflammatory Th17 cells and regulatory T cells is disrupted, while populations of regulatory B cells and invariant natural killer cells in adipose tissue dwindle. Increased lipolysis releases free fatty acids that recruit pro-inflammatory M1 macrophages and activate the NLRP3 inflammasome, driving secretion of the interleukins IL-1β and IL-18, cytokines deeply implicated in autoimmune pathology. Perhaps most provocatively, dying adipocytes can release antigens previously hidden from immune surveillance, potentially triggering autoreactive responses. Two complementary frameworks, the accelerator hypothesis and the overload hypothesis, propose that obesity-driven insulin resistance forces beta cells to work harder, accelerating their apoptosis and increasing their immunogenic visibility to the immune system.

This mechanistic overlap gives rise to two distinct hybrid phenotypes. Double diabetes refers to patients with type 1 diabetes who develop overweight, insulin resistance, and metabolic abnormalities characteristic of type 2 diabetes, often with a family history of the latter. LADA, by contrast, is a slowly progressive autoimmune diabetes that emerges in adults who frequently present with clinical and metabolic features resembling type 2 diabetes at onset. Both conditions carry a substantially elevated risk of complications. The FinnDiane study found that individuals with double diabetes had a hazard ratio of 2.52 for diabetes-related mortality compared to those with type 1 diabetes without metabolic syndrome. The review attributes this heightened risk to the combination of insulin resistance, altered cardiovascular risk factors, and a chronic low-grade inflammatory milieu that promotes endothelial dysfunction and oxidation of atherogenic LDL cholesterol.

Distinguishing these hybrid phenotypes from classical diabetes subtypes requires tools that go far beyond clinical observation. The review synthesizes evidence from genomics, miRNomics, metabolomics, and microbiomics to construct a multi-omics picture of disease heterogeneity. Genetic studies reveal that LADA shares substantial etiological overlap with type 1 diabetes, particularly at the major histocompatibility complex region and at genes including PTPN22, SH2B3, and the insulin gene, while showing only modest contributions from type 2 diabetes susceptibility variants aside from a notable signal at HNF1A. Notably, the class I MHC effects characteristic of childhood-onset type 1 diabetes are absent in LADA, providing a genetic discriminator between the two autoimmune subtypes. In double diabetes, Mendelian randomization analyses support a causal role for childhood adiposity in elevating disease risk, while polymorphisms in the KLF14 locus modulate cardiometabolic and inflammatory profiles in young patients with type 1 diabetes.

Circulating non-coding RNAs have emerged as particularly promising biomarkers for differential diagnosis. Plasma-derived exosomal miRNA profiling identified 75 dysregulated species in LADA, with three candidates, miR-146a-5p, miR-223-3p, and miR-21-5p, demonstrating strong discriminatory performance between LADA and type 2 diabetes. Circular RNA analysis revealed extensive dysregulation implicating TNF signaling, FoxO activity, and cellular senescence pathways. At the metabolomic level, LADA does not exhibit a unique metabolite signature but rather occupies an intermediate position between type 1 and type 2 diabetes, with patients whose profiles overlap more closely with type 1 diabetes progressing more rapidly to insulin therapy. Gut microbiome studies have identified disease-specific alterations in beneficial taxa such as Bifidobacterium species and their correlations with branched-chain amino acids and short-chain fatty acids, suggesting that dietary interventions targeting the microbiota could modulate both metabolic and immune pathways.

On the therapeutic front, the review highlights a growing arsenal of drugs originally developed for type 2 diabetes that show promise in hybrid phenotypes, largely because of their anti-inflammatory properties alongside their glucose-lowering effects. Metformin, SGLT2 inhibitors, DPP-4 inhibitors, and GLP-1 receptor agonists have all demonstrated improvements in insulin sensitivity, body weight, and cardiometabolic parameters when used as adjuncts to insulin therapy. The ADJUNCT trials showed that liraglutide added to insulin in type 1 diabetes reduced HbA1c, body weight, and daily insulin requirements, though with increased risk of hypoglycemia and ketosis. More recently, semaglutide has shown impressive results: the ADJUST-T1D trial demonstrated that semaglutide combined with automated insulin delivery significantly increased the proportion of adults achieving time in range above 70 percent alongside meaningful weight loss, while the ENDIS study showed improvements in endothelial function and reductions in high-sensitivity C-reactive protein, a key inflammatory marker. The dual GIP/GLP-1 receptor agonist tirzepatide has shown substantial reductions in HbA1c and body weight in GADA-positive patients previously diagnosed with type 2 diabetes, with associated improvements in beta-cell function markers.

Perhaps the most clinically actionable insight from the review concerns the role of C-peptide, a byproduct of insulin production that serves as a proxy for residual beta-cell function. Experts suggest that patients with fasting C-peptide levels below 0.3 nmol/L should be treated with insulin alone, those between 0.3 and 0.7 nmol/L may benefit from glucose-lowering drugs combined with basal insulin, and those above 0.7 nmol/L can be managed with algorithms typically reserved for type 2 diabetes. This stratification is supported by evidence that dulaglutide was less effective in LADA patients with low C-peptide levels, while semaglutide as add-on therapy significantly improved glycemic control, reduced body weight and insulin requirements, and increased C-peptide levels particularly in those with preserved beta-cell function. The review also proposes a novel concept: a standardized multi-omics and genetic approach could identify what the authors term a double diabetes risk inflammatory signature, or DRIS, to enhance patient stratification for tailored therapeutic approaches.

The challenges ahead are substantial. The molecular phenotype of double diabetes remains poorly characterized, limiting recognition and distinction from other hybrid forms. No randomized clinical trials have specifically evaluated immunomodulatory therapies such as teplizumab, which has shown efficacy in preserving beta-cell function in early type 1 diabetes, in patients with LADA or double diabetes. The review emphasizes that larger, longitudinal studies are urgently needed to unravel the mechanisms by which hybrid forms develop and to determine whether certain therapies offer superior benefit in specific subgroups. What is clear is that the era of treating diabetes as a binary condition is drawing to a close. As the boundaries between autoimmune and metabolic disease continue to dissolve, precision medicine approaches that integrate genetic susceptibility, inflammatory biomarkers, and multi-omics signatures will be essential to identify the right treatment for the right patient at the right time.

Subject of Research: Inflammatory mechanisms and multi-omics biomarkers in hybrid diabetes phenotypes including double diabetes and LADA

Article Title: Decoding inflammation to target hybrid diabetes phenotypes

Article References: Rossi, G., Terranegra, A., Lunati, M. E., Pastore, I., Pozzi Canova, L., Bucciarelli, L., Cimino, V., Loretelli, C., Ben Nasr, M., Fiorina, P., & D’Addio, F. (2026). Decoding inflammation to target hybrid diabetes phenotypes. Frontiers in Endocrinology, 17, Article 1922969. https://doi.org/10.3389/fendo.2026.1922969

Image Credits: AI Generated

DOI: 10.3389/fendo.2026.1922969

Keywords: diabetes, inflammation, obesity, LADA, double diabetes, immunology, precision medicine, endocrinology, GLP-1 receptor agonists, multi-omics, Decoding, target

Autoimmune thyroid diseases affect millions worldwide, with Hashimoto’s thyroiditis standing as the leading cause of underactive thyroid function and Graves’ disease driving most cases of overactive thyroid. Both conditions arise when the immune system mistakenly attacks the thyroid gland, but the environmental triggers that set this process in motion remain incompletely understood. The gut microbiome has emerged as a compelling suspect because of its established role in training and calibrating the immune system. Gut bacteria ferment dietary fibers into short-chain fatty acids such as butyrate, propionate, and acetate, molecules that nourish the intestinal lining and help maintain the delicate balance between immune tolerance and inflammatory reactivity.

The research team, led by investigators applying rigorous PRISMA guidelines, systematically searched major databases including PubMed, Scopus, and Web of Science for studies comparing gut microbial composition in patients with autoimmune thyroid disease against healthy controls. After screening hundreds of records and applying strict inclusion criteria, the analysts pooled data from 30 qualifying studies. These investigations employed 16S ribosomal RNA gene sequencing to catalog bacterial communities in stool samples, allowing researchers to quantify differences in microbial diversity and abundance between patient and control groups with statistical precision.

The meta-analysis revealed a striking and consistent finding: individuals with autoimmune thyroid disease exhibit significantly reduced gut microbial diversity compared with healthy individuals. This reduction in alpha diversity, a measure of the variety of species within a single person’s gut, suggests a less resilient and less functionally versatile microbial community. Reduced diversity has been linked to a range of inflammatory and autoimmune conditions, and its presence in thyroid autoimmunity reinforces the hypothesis that microbial imbalance, or dysbiosis, may contribute to disease development rather than simply accompany it.

Beyond overall diversity, the analysis identified specific bacterial groups that consistently differ between patients and controls. Beneficial butyrate-producing bacteria, including members of the genera Faecalibacterium and Lachnospira, appear depleted in individuals with Hashimoto’s thyroiditis. These organisms are key suppliers of short-chain fatty acids that strengthen the gut barrier and promote anti-inflammatory immune signaling. Their reduction could weaken the intestinal lining, allowing bacterial fragments to cross into the bloodstream and trigger immune responses that cross-react with thyroid tissue, a mechanism known as molecular mimicry.

At the same time, the analysis documented an expansion of potentially pro-inflammatory taxa in patients with autoimmune thyroid disease. Species associated with lipopolysaccharide production, an inflammatory bacterial cell wall component, were enriched in patient groups, alongside increases in opportunistic organisms such as certain Escherichia and Shigella species. This shift in microbial composition toward inflammation-promoting bacteria provides a plausible biological pathway through which gut dysbiosis could fuel the chronic immune activation that characterizes thyroid autoimmunity.

The findings also revealed distinct microbial patterns between Hashimoto’s thyroiditis and Graves’ disease, suggesting that these two conditions, while related, may involve different gut microbial contributions. In Hashimoto’s thyroiditis, reductions in beneficial SCFA-producing bacteria were particularly pronounced, whereas Graves’ disease showed its own pattern of altered abundance in specific taxa. These differences hint that microbiome profiling could eventually help clinicians distinguish between autoimmune thyroid conditions or identify patients at risk of progression, although the researchers caution that the current evidence remains observational.

Importantly, the meta-analysis found that microbial alterations were not simply a consequence of thyroid hormone imbalances or medication use. Subgroup analyses examining patients at different stages of disease and treatment status indicated that dysbiosis persists across clinical contexts, supporting the idea that gut microbial changes may precede or actively participate in disease development. However, the cross-sectional design of most included studies prevents definitive conclusions about cause and effect, and the researchers emphasize that longitudinal studies and interventional trials are needed to establish whether microbiome changes drive thyroid autoimmunity or merely reflect it.

The implications of this work extend beyond basic science into potential clinical applications. If the observed microbial signatures can be validated in larger, prospective cohorts, they could inform the development of microbiome-based diagnostic tools or guide the use of targeted probiotics, dietary interventions, or fecal microbiota transplantation as adjunct therapies. Several strains of Lactobacillus and Bifidobacterium have shown promise in small studies of autoimmune conditions, and the current analysis provides a rationale for testing whether such interventions could modulate immune activity in thyroid disease. The researchers also highlight the need for standardized sequencing protocols and reporting guidelines to reduce heterogeneity across future studies.

As autoimmune thyroid disorders continue to rise in prevalence globally, driven by factors ranging from iodine intake to environmental exposures, understanding the contribution of the gut microbiome has become an urgent research priority. This meta-analysis consolidates a rapidly expanding literature into a coherent framework, confirming that microbial dysbiosis is a reproducible feature of autoimmune thyroid disease and pointing toward specific bacterial targets for future investigation. While much work remains to translate these associations into therapies, the study marks a significant step toward a more integrated view of thyroid autoimmunity, one in which the gut microbiome plays a central role in disease susceptibility, progression, and potentially treatment.

Subject of Research: Gut microbiota alterations in autoimmune thyroid disorders revealed by systematic review and meta-analysis

Article Title: Retraction: Exploring the role of gut microbiota in autoimmune thyroid disorders: a systematic review and meta-analysis

Article References: Frontiers Editorial Office (2026). Retraction: Exploring the role of gut microbiota in autoimmune thyroid disorders: a systematic review and meta-analysis. Frontiers in Endocrinology, 17, Article 2023216. https://doi.org/10.3389/fendo.2026.2023216

Image Credits: AI Generated

DOI: 10.3389/fendo.2026.2023216

Keywords: gut microbiota, autoimmune thyroid disease, Hashimoto's thyroiditis, Graves' disease, dysbiosis, meta-analysis, thyroid hormones, short-chain fatty acids, intestinal permeability, microbiome, systematic review, endocrinology